HarmonicCoefficients

class ssapy.gravity.HarmonicCoefficients

Bases: object

Class to hold coefficients for a spherical harmonic expansion of a gravitational potential.

Methods Summary

fromEGM(filename)	Construct a HarmonicCoefficients object from a .egm/.cof file pair as available from https://geographiclib.sourceforge.io/html/gravity.html
fromTAB(filename[, n_max, m_max])	Construct a HarmonicCoefficients object from a .tab file as available from https://pgda.gsfc.nasa.gov/products/50

Methods Documentation

classmethod fromEGM(filename)

Construct a HarmonicCoefficients object from a .egm/.cof file pair as available from https://geographiclib.sourceforge.io/html/gravity.html

SSAPy comes with four models for Earth gravity of varying degrees and orders:

name | degree | order

WGS84 | 20 | 0 EGM84 | 180 | 180 EGM96 | 360 | 360 EGM2008 | 2190 | 2159

Note that many coefficients with large degree and/or order underflow double precision floats when denormalized for use in computing accelerations and are therefore effectively ignored.

param filename:

Either the name of the .egm file or one of the names listed above.

type filename:

str

classmethod fromTAB(filename, n_max=40, m_max=40)

Construct a HarmonicCoefficients object from a .tab file as available from https://pgda.gsfc.nasa.gov/products/50